Although a shear flow field and beta-nucleating agents (beta-NAs) can separately induce the formation of beta-crystals in isotactic polypropylene (iPP) in an efficient manner, we previously encountered difficulty in obtaining abundant beta-crystals When these two factors, were applied:due to the competitive growth of alpha- and beta-crystals. In the current study, to induce the formation of a high traction of beta-crystals, a strategy that introduces a relaxation process after applying a Shear flow field but before cooling to crystallize beta-nucleated iPP was proposed. Depending on the relaxation state of the shear-induced oriented precursors, abundant beta-crystals with a refined orientation morphology were indeed formed. The key to producing these crystals lay in the partially dissolved shear, induced oriented precursors as a result of the relaxation process's ability to generate beta-crystals by inducing the formation of needlelike beta-NAs. Therefore, the content of beta-crystals gradually increased with relaxation time, whereas the overall crystallization, kinetics progressively decreased. Moreover, more time was required for the content of the beta-phase to increase to the (maximum) value observed in quiescent crystallization than for the effect of flow on crystallization kinetics to be completely eliminated. The c-axis of the oriented beta-lamellae was observed to be perpendicular, rather than parallel, to the fiber axis of the needlelike beta-NAs, as first evidenced by the unique small-angle X-ray scattering patterns,obtained., The significance of the relaxation process was manifested in regulating the content and morphology of oriented beta-crystals in sheared, beta-nucleated iPP and thus in the structure and property manipulation of iPP.